I would think that if a person has skin problems like pimples within the confines of a beard that the indirect cause is facial hair. I say indirect because I have known guys over the years with beards some of whom have had acne like conditions in the beard but not the rest of the face, and it stands to reason that the unhairy areas get cleaner when scrubbing the face than areas that are covered by hair. And I don't know the answer except to keep it short or shave it off altogether so that washing the face also allows cleaning of the pores within the beard.
But that's just, like, my opinion, man.